U.S. President Barack Obama has called for renewed focus on "nation building" at home after a decade of war in Afghanistan.

In his weekly address before hitting the campaign trail in Ohio and Virginia, Obama recapped his trip earlier in the week to Afghanistan, where he signed a strategic partnership agreement with President Hamid Karzai and marked the anniversary of the killing of Osama bin Laden.

"Because of their [U.S. military's] bravery and dedication, the tide of war has turned in Afghanistan. We have broken the Taliban's momentum. We've built strong Afghan security forces," Obama said.

"We have devastated Al-Qaeda's leadership. And one year ago, our troops launched the operation that killed Osama bin Laden," he added. "The goal that I set -- to defeat Al-Qaeda and deny it a chance to rebuild -- is within reach."

Obama said that another 23,000 U.S. soldiers would leave Afghanistan following the 10,000 that left the country last year.

He said that by the end of 2014 Afghans will be "fully responsible" for the security of their country.

'Nation Building At Home'

Obama praised the strategic agreement with Afghanistan. He said it would help both nations to achieve an enduring partnership.

"Because of the progress we have made, I was able to sign an historic agreement between the United States and Afghanistan that defines a new kind of relationship between our countries," Obama said, "a future in which Afghans are responsible for the security of their nation, and we build an equal partnership between two sovereign states; a future in which the war ends, and a new chapter begins."

In what appears will be a key campaign slogan this summer, Obama called for "nation building here at home" after a decade of costly foreign wars.

Obama first official campaign rallies will be in Ohio and Virginia on May 5. Both are considered battleground states that could be key to his hopes of winning a second term in November.